Giant Ice Shelf Breaks Off in Canadian Arctic

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"We can't say that this [specific] event is due to global warming, but it definitely fits the long-term trend."

The summer of 2005, Copland said, had the lowest amount of Arctic Ocean sea ice ever recorded.

Pack ice normally buffers the ice shelf from ocean movement. But with little ice and strong offshore winds, waves were able to batter the ice shelf, weakening it.

In addition, 2005 was the warmest summer recorded on Ellesmere Island since 1960, with temperatures about 3.8°F (2.1°C) above average.

And the ice shelf breakup wasn't the only geologic disturbance on the island that summer.

Antoni Lewkowicz, a geography professor at the University of Ottawa, happened to be on the island when the ice shelf disintegrated, although he was unaware of the event at the time.

For nearly 20 years Lewkowicz has been studying landslides triggered by melting permafrost.

The overall warm summer thawed out the island significantly, he said, and a week of strong sun at the end of July set off massive numbers of landslides.

"You need a blast of heat," he said. "And that's what happened—a week of clear weather and warm temperatures, which triggered a whole bunch of landslides literally all around us."

In one 3.5-square-mile (9-square-kilometer) tract he counted 50 landslides during the warming period.

"So there were reactions to that warm period on the land as well," he said.

Lost Treasure

The broken ice shelf and Lewkowicz's landslides are important indicators of global climate change and its effects on the polar ice caps.

Earlier this month scientists reported that global warming may mean that the Arctic Ocean's summer sea ice will be completely gone by 2040.

And recent studies have shown that a loss of Arctic ice is causing polar bear populations to plummet, leading to a proposal to include the bears on the U.S. endangered species list.

Copland adds that the ice shelves are valuable because they offer a variety of historical and ecological insights.

Creatures that survive in such extreme environments, for example, could be analogues for life on other planets.

Arctic ice shelves are "not as sexy as polar bears," Copland said.

"But these are very unique environments, and we just lost one of them."

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